Asset/Workstation purchasing

I am just trialling out SD+ to see how i get on with it. Can someone just help me understand the procedure for purchasing assets.

If i build a purchase order for a workstation, once received it goes into the assets table.

Once it is on the network i scan it for details and it is located in the workstations table. so affectively i have it listed twice. Is this how its meant to be, maybe i am just misunderstanding it.

Also i have created a field for workstations called warranty expiry (pretty cruicial i would have thought, dont know why it was missed out!) yet it only appears when you manually add workstation not when you scan the network.

Can anyone help